Rack and pawl actuated quickacting clamp



June 7, 1949. C. L. GILBERT 2,472,658

RACK AND PAWL ACTUATED`QUICK-ACTING CLAMP Filed Aug. 17, 1945 2Sheets-Sheet 1 June 7; 1949. Q ILBERT y 2,472,658

RACK AND PAWL ACTUATED QUICK-ACTING CLAMP Filed Aug. 17, 1945 2Sheets-Sheet 2 Z//libllmu www L A ,5 ,7, lv

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35// 33 j mm1@ 'Z725 Z3/ 1| i lim l 7' /0 Patented June 7, 1949 RAGE-ANDPAWL AOTUATEDiQUICEf ACTING CLAMP Clyde-'Ll Gilbert, Elkhart; IfldpApplication August'l', 1945, Sri'l NouGIILSZl`-` .-Clams.. Cl.144--305-)- This .t inventiomrelatesatoua; handrclamp; f

The chief obgi'ectr:oithisrzinventiorrlis toafpro.- vide a quick acting;oneehanttoperable; positive lockingfzG-clamqoa.:

The:y chief'y feature: of@ th'e :inlventom resides :in the simplicity ofconstructompositiveness,ofrop eration; anradinsliabilityo'theaclanfiptlThe inventionisfcharacterizectfby at @shaped body, providdu atiits.'-.midiiportion withzaanger gripvsocketpan operatingilever thatvlocksxf over'- center-z in ljuataposijion.m to'rthe "grip",r` ai cam 1op:- erablefl paw-l; au clampinrgf: head#l supporting:` rackrapidilymovable `Atowardandl"away ifronr=an= anvil por-tioni` of'th'eb'ods'fffandl b'y gravitygand" cam pawls movable intoworklooki'ngepositi'on",` together with-`A a" work" engaging head," cushiomvsupported for rack impact shock alosorptorft;A andmicro'-metrioally-adjustablefrelativeito: theiraclc.

The 'fuili 'naturefothefinvention iwill loe Eunder'- stoodfromlthe'accompanying drawingsand'the following'-descriptirmv and claims:A4

Inf thei drawings,

Fig. 1 is a side elevation 'of f embodiment' of the invention with`partsIwork'eng-agingv posi'- ti'on; oneecornnation 'cover andlfame--p1ate"-be ing removedfforiclearness;

Fig; 2isf a rear'felevationofsuch embodiment, the-"actuating'part'being'fb'roken -aawayfandf-shown insection to better-illustratetHe-cover andffr'ame plate-structuree Fig-.f 3Y-is`- any enlargedlcentra-I Vsectional view of the Head-'end offthevsupporting rack;the-'Work enga-ging* head,l and* thefuniversal, resilient vandadjustableYconnection-therebetween.

Fig: 4 is aviewl'similarltofl'gt L lb'ut of ther-rack, pawl; operatingleverandimmediatly'associated parts only and in the released,orc-'quickl action position;

Fig: Sis a vi'ewsimilarftofli'ga Ll-fwith parts shownr irraf positioninternlediatel'ietvveenk those illustratedin igss land 4i- In' thedrawingf I=0 indicates 1 as conventionally termed Gshaped* body@portion"- terminating at one"end"in the '-anviflfportlorr Ix IiThis-body por'- tionisreeniorced 'by-af cential ri-Eorv-n I'Zi'whichadjacent"tlie'midiportionof the lbody isfvenlarged asat"I3"and^'apertured at- III' tiformfformfwnger grip" or s ocket;

The upper end I5 of the body I0 does noti-extend-forwardly'asf-farasetheeanvillportiou`v I Ibut terminatesfshort thereof asiat If.Extending upwardly therefrom-lis `a"hase'sec-tion ITI-'fwhicli--isshouldered*longitudinally asiat-| I 8i Annuaire oiconrp'lementaryfcombination cover andzfra-mei fom-linggfplates;Ifhave-inwardly'vfdirected' rear endziiangesaZIlwhfch. ahutfat 12 IiOpposite-a'thereto are'A the inwardly f directed f front enddianges-Z2^; Theflowerzport'rons `of :said plates straddlefthegprojectingmortionfor;basefI I= fandtall axxesuita'laly1 secured:together-'hm screws,A rivetssor the ikei2'3'@ Theerear. ilangesiZufarexcut away;t as-:at 24..-to accommcdaiiecthe:rlo'ase; |112, Base:yI"I-f extends-up;- wardlyfandr.forwardlwsaszat i25nand includes: face26a parallel.l-` tof'flangess:z'forming: :therewith and pl'ateslSiaz'rectangularisoclcetla;

Slidable longitudinailwn the;soclcet,21-v and along tli'etangesf. 22'iiserstem 28 ;f rectangu'lamfin transversepf section and having rack'.;Lteeth1 29 formed: in: facea30toppositei thez'facethat slides on: angeslTwo pirxslv 3 I andl 32;'extend across va the: 1 plates I9 andconstitute xed bearings'.:andmayzfbe: of rivet;E charactem ton securether: plates: together. slid-ably andzpivotallmmonnted onzfpin-zrcis,vthe campawl133ihaving the.elongated.'51017.34y therein,whichIrides.pinfZz'H Thaforwardfzendderminates -in the rack:engagingtteeth'ii 5t offwhic'h therel arethree;-Whioliterminateiiniarcuately arranged tips. Two teth': alwayscarry thefloadi due 1 to such arcuity:

'Ihe@oppositeendisfreducedi atl 36%to @forniva -projectionf seatableifincoil sprinfgfl' I bearingl on shoulder 382; Thlisffprog'ection"and; aportionof the body 33 is recessed at 39 and slidabler'thereinis'fsterntz llllfwh'ich;y sp'aeed ffromf'fpawl-'if 33'; carries headfIIIagainst whiolilthe otherxend-of said Sprit-ig'l 31W bears: Stem 401Wexister-rds. through :the springc andi head' 4 IIiisi-1l curved.'` on:its rear 'face assat42.torbearluponanges The latter 'I include :thevcentral;y elongatedfl slot 431 therein, inw whichfrrides: extension 44yof I the ystem dlandfheadf'll Springlf therefore; nor= Ina/?constrainsfpawly 33H toward-f racklengagementi. Since :therpawl ridesf`statici-ilary" pin 32 through elongated: slot'y 311;-1 azleafspringihas/its forward i bend i end .v 46 bearing: upwardly against the lowervface of pawl'f 33 adjacent teeth-35 thereof.- AscrewLlIfI orv the-likesuitably y anchors the'fopposite endffot'sai'dispringfll!toibasef II,las i1litstratedaV Hence, spring-:45normallyrconstrains pawl'I33fupward1yrat itsforwardlend lor,' in effect, -towardicloclw/iserfrotation'ondpivot 32;.:

Pivotally y'mounted"onf the lotlierf pivot y3iI`= is'- a camlevert-48*Whichzmounts hardened sl'e'evefds. This' leveri -h'a'sfa@attforwardc face. 50i that L just clears rack teeth 29 when.tlief'rl'everiistilted-"into f 'lockingandfholdinguposition.otherffwords,

face 58 is opposed to ilanges 22 and forms therewith and plates I9 asecond and elongated socket 21a in registration with socket 21aforesaid, so that canting of said rack is prevented.

The lever, adjacent face 59, is arcuately formed as at I, the radius ofsame being the distance approximately equal to that between the axis ofpivot 3l and the faces of teeth 29. Lever 48 includes elongated handle52 that initially extends rearwardly and downwardly and then extendsdownwardly and forwardly as at 52a to conform to the linger grip portionI3 when the lever 48 is tilted clockwise and locked over-center inholding position.

Lever 4B, below pivot 3l, includes two spaced and opposed faces 53 and54 on its lower face and therebetween is intermediate cam portion 55.Extending upwardly as at 56 from the upper confronting face of the pawl33 is the abutment providinT opposite faces '51 and 58 and the centrallyrelieved intermediate face 59 relieved as at 6U.

Fig. 1 illustrates the several parts in clamping and locked relationrelative to work W. In this position the tail portion 52a is immediatelycontiguous to guard I3 and shoulder or face 54 of lever 48 is inengagement with shoulder or face 58 of pawl 33 and holds same forwardlywhile cam 55 engages face 59 of the pawl to hold the pawl against spring45 and hence hold the rack down, so that head 60h lclamps work W betweenit and anvil II for teeth 29 and 35 are engaged.

When handle 52 is elevated, see Fig. 4, shoulder or face 53 is engagedwith shoulder or face 51 and the pawl 33 is retracted rearwardly againstspring 31. Pin 32 limits this movement. Teeth are now free of the rackteeth 29 and the rack 28 and head 60b with the interconnectiontherebetween may be freely slid toward and away from anvil II. Springnow holds pawl 33 elevated.

When clamping is desired, the clamp may be held in one hand with partspositioned as shown in Fig. 4 and inverted until the rack is fullyretracted. The other hand then presents the work W to the clamp, thework bearing on anvil I I and the rack 28 dropping head 60h into workengagement when the clamp is positioned as shown in Fig. 4. Then handle52 is depressed which depresses pawl 33 against spring 45 and subject tothe stop function of shoulder 53 engaged with shoulder 51, the teeth 35loosely mesh with rack teeth 29.

Continued clockwise rotation of lever 48 by further depression of handle52 removes pawl 33 from the aforesaid stop limitation and cam now passesfrom depression 6I) to face 59 and forces the pawl 33 counterclockwisefrom the position shown in Fig. 4 toward the position shown in Fig. l.As this occurs shoulder 54 approaches shoulder 5S. Final lever movementforces head Sill) down on the work with the desired pressure and lever48 locks over-center, as it were, such center being approximately thatdefined by a plane through the axes of pivots 3| and 32.

Actual clamping pressure is initially exerted when cam 55 starts toleave depression 60. Maximum clamping pressure is attained when cam 5'5engages face 59. Thereafter lever movement is solely for lockingover-center and positioning shoulder 54 immediately behind shoulder 58to prevent accidental release of the cam lock on the rack and to retainthe clamping pressure. The rack throw, by reason of cam 55 isapproximately the width of two teeth.

Reference will now be had more particularly to Figs. l and 3. The head his slightly concaved or dished as at 60a. It includes a partiallyspherical socket BI closed by collar portion 62 and therein is ball 63having stem 64 extending from the collar. Stem 64 is carried by portionS5 that is slidable in socket 56 of member 61 having shank 58 reducedexternally as at 69 and threaded as at 19. The lower end of rack 28 isapertured at 1I and threaded as at 12. By this means the shank 68 andhead 60h can be advanced or retracted relative to the rack 28.

In Fig. 3 the adjustment is exhausted upwardly and available downwardlyto the maximum degree. Fig. l shows slight downward adjustment.

For cushioning impact member E5 includes stem 13 and both are tapped andthreaded as at 14. Shank G8 is recessed as at 15, same constituting areduced extension of socket and providing shoulder 1B therebetween.Shank 63 includes apertured 'partition 11 apertured at 18 and recessedat 19 to take head 80 of the boli"I having the .threaded body portion 8|threaded into tapped portion 14. A coil spring 82 envelops the bolt andsleeve extension 13 and bears at one end on face 83 of portion IB5 andat its opposite end on partition 11.

When the head is dropped member =65 telescopes into socket 55 and iscushioned lby spring 82. This can fully collapse into bore 15 when face83 engages face 16 when clamping pressure is applied to the rack 28. Ifthe rack clamping movement, following such collapse, be insuiicient toproperly hold the work W, the externally knurled portion B1 is rotatedto adjust the head `60h relative to rack 28 so that proper pawl clampingpressure is obtained when lever handle 52 is tilted clockwise.

Having thus described the respective parts and briefly outlined themajor features of operation thereof, it is now further pointed out thatinvention, as illustrated, by reason of the slidable extension on thetoothed pawl or detent limits the clockwise rotation thereof about theaxis of the pin and slot connection by reason of the lower end of theelongated slot 43 formed in the two rear flanges of the plate I9.

The lever pivot with its axis and the pawl or detent pin axisdetermines, as aforesaid, a plane and when the lever is sufficientlytilted clockwise it vpasses over center, as it were, and isself-sustaining in the over center position. When fully moved to theover center position the detent is locked, as aforesaid, against rackrelease and at the same time the free end of the lever isjuxtapositioned or closely associated with the ringer grip portion I3 ofthe clamp body and preferably the end of that lever has slight clearancerelative to the lateral projection of the lowermost portion of the bodyI 2.

If it be assumed that the pawl or detent incident to the cam actuationforces the rack and the head toward the work for a predetermined amountof travel in the clamping direction, then the cushion spring of thecushion connection is of such character that when it is collapsedsuiliciently for the two stop shoulders 16-83 to contact, the cushiontravel, as it were, constitutes only about als of an inch orapproximately 7/ of the pawl responsive rack travel, same beingapproximately 1/4 of an inch, by way of example only.

It will be obvious .that any desired pressure application can beimparted by the head 50D for clamping the work between the head and theanvil portion, if within the range of pressure deeee-agees terminaioleby the leveragel and the cam,l etofviously, itgreatpressure is desiredVand'orilyyli'mited rack travel-is ava-ilablronly; lightf-pressure willbe obtained. Consequently; the threadedad-s justmentconnection 8-I'!1t`aforesaid between the clamping head and thel rackfmemb'eri can beadjusted so thatthe desired-i clampingf'pressure will berobtained-fertile operative andfeniective travel of the rackmember, the;detentta'n'd'lthe cam lever, andsuch-v adjustmenty for yincreasedpressure is 'obtained -by-unthreading thefthireaded connection to thedesired degree and a decrease in pressure is obtainable by threadingyoperation to the desired degree.

The dished type head insures peripheral or circular contact with thework as distinguished from point or axial conta-ct with the work. Theball and socket connection permits :angular adjustment of the head tolconform to any flat surface and also permits positive engagement withany other surface having a curvature of greater radius than that of theconcavity in the head and permits point bearing contact, as it were,with any surface that has a curvature of greater arcuity than that ofthe concavity of the head.

It will be further noted that the invention her-em disclosed exerts auniform, straight and even pressure without any twisting eiect, etc.,upon the work. Also, the nger hole arrangement in the body of the clamphas the further feature that the clamp body vSpaces the fingers from thework and this is particularly advantageous when a piece of hot work isto be held by a clamp for welding or like purposes or a hot tool is tobe associated with work held by the clamp. Body I0 here also serves as ashield.

The invention has the further advantage that if the smallest size clamphas its body portion provided with maximum sized finger grip and it isdesired to utilize standard parts for this size, the -only requisitechanges will be to substitute for the body illustrated a body having alarger throat, as it were, or a smaller throat and provide a rack ofgreater or less length, respectively, all other parts remaining thesame.

It will be further noted that the offsetting in the body portion at theend opposite the anvil end and the oisetting in the plates I9 permitsthe positioning of the head when fully retracted in a nested arrangementso that substantially the body full opening is available for workreception and all without enclosing the knurled adjustable member forit, in this position, is exposed at three sides and can be fingeradjusted for pressure variation as previously described.

While the invention has been illustrated and described in great detailin the drawings and foregoing description, the same is to be consideredas illustrative and not restrictive in character.

The invention claimed is:

l. In a clamp structure having van anvil and a work clamping headmovable toward and away from same, the combination of a reciprocablerack toothed member supporting the head, a lever pivotally mounted inspaced relation to the member, a multiple-toothed member movable towardand away from the rack toothed member for tooth engagement anddisengagement, lever operable cam means for moving the second mentionedtoothed member toward the anvil for effecting rack member and headmovement toward the anvil for work clamping purpose, said lever operablecam means and said multipletoothed member each having a pair of spacedoptoothed mem-bentowardrackf-z engagenrent. lever operationfretractingthe multiple-toothed mem ber in opposition to the constraining means, atleast two teethA otthemultiple-toothed member having engagement :withthey racletoothed :member when the latter exerts pressure-upon the head.

2. In a'clamp"'structure"having 'an' anvil and a worlc-ciamping headmovableftoward andraway from. same, the combination: of a reciproeablerack toothed member supporting the head, a lever pivotally mounted inspaced relation to the member, a multiple-toothed member movable towardand away from the rack toothed member for tooth engagement anddisengagement, lever 0perable cam means for moving the second mentionedtoothed member toward the anvil for effecting rack member and headmovement toward the anvil for work clamping purpose, mounting means of apin and elongated slot type for the multipletoothed member, the slot ofsaid means being directed generally longitudinally with respeci'I to themultiple-toothed member, and yielding means normally constraining themultipletoothed member away from the anvil, and in opposition t0 the cammeans operation thereof.

3. A clamp structure as defined by claim 2 wherein the multiple-toothedmember has pivotal movement about; the pin axis of said mounting means,a tail slidable longitudinally with respect to the multiple-toothedmember, guide mechanism of pin and elongated slot type and associatedwith that tail, and yielding means interposed between the multipletoothed member and the guide mechanism constraining that member and tailtoward extended position.

4. In a hand clamp having a clamping head supporting rack, and amultiple-toothed member movable toward and away from Same for engagementand disengagement therewith, the combination of a cam provided leverpivotally mounted in juxtaposition to said member and having a camportion arranged upon lever actuation to engage and move said member,rack and head into the clamping direction, and shoulder means on thelever and member adjacent the cam engaged portion of the member forpredetermined engagement upon predetermined positioning of the lever,the lever, when the shoulder means is engaged, having a self-sustainingover-center position, the shoulder means on the lever and the memberbeing disposed at opposite sides of the cam portion and cam engagedportion and each comprises opposed shoulders, one adjacent pair ofshoulders when engaged and the lever is suilciently tilted in onedirection effecting retraction of the member from rack engagement, andthe other adjacent pair of shoulders when the lever is suciently tiltedin the opposite direction preventing accidental disengagement of themember from the rack.

5. In a clamp having an anvil, anopposed head and a member for movingthe latter toward and away from the anvil for clamping and releasepurpose, the combination of a connection between the member and headcomprising an intermediate member, complementary ball and socket meansbetween the head and the intermediate member, a second intermediatemember between first mentioned member and the iirst mentionedintermediate member, adjustable yielding means between the intermediatemembers which are tioned intermediate member together.

CLYDE L. GILBERT.

REFERENCES CITED The following referen'ces are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 438,850 Lockwood Oct. 21, 1890Number 8 Name Date Walker May 2, 1893 Wrigley Jan. 9, 1906 Stewart Apr.11, 1911 Krahulec Mar. 18, 1913 Parsons Nov. 15, 1927 Miller Jan. 19,1943 Kellogg Apr. 6, 1943 Gordy et al July 6, 1943 Kirlin Aug. 3, 1943Gearhart Feb. 13, 1945

